Left turnings save time

Abstract

This paper reports an experimental study which investigated the effect of the direction of turn on walking speed on curved paths. The results show that the time required to walk a curved path anticlockwise (a left-hand turn) is significantly less than the time required to walk the same path clockwise (a right-hand turn). Effects of the radius or arc followed at the turn of load have also been investigated.     

Software lives too long

Old programs represent yesterday's technology. We have has learned quite a bit about software engineering methodology in the last few years. We now know, for example, that requirements traceability is central to program maintainability-if we don't know what a program is supposed to do we cannot maintain it. We know that calendar years have four digits in them, not two. We know that data can best be managed in databases. We know that many of the utility functions once written into programs are best handled by the operating system. And we have new design constructs and new programming language features that permit us to design eminently maintainable programs. When the cost of maintaining old buildings becomes excessive, we replace these buildings. We must do the same with old programs. Programs do not age well-written for hardware systems and operating systems that typically no longer exist many are fraught with undocumented patches and features. Just as we have learned that it is wise to invest in new hardware and new buildings, we must learn to recognize the value of replacing drafty and rickety old software     

Digital libraries

The history of modern information processing and the technology underlying it is reviewed. The development of hypertext is examined. Current technology and current efforts to expand information processing are discussed. The future of digital libraries is outlined     

Toward cinematizing our daily lives

We introduce a cinematographic video production system to create movie-like attractive footage from our indoor daily life. Since the system is designed for ordinary users in non-studio environments, it is composed of standard hardware components, provides a simple interface, and works in near real-time of 5 ~ 6 frames/sec. The proposed system reconstructs a visual hull from acquired multiple videos and then generates final videos from the model by referring to the camera shots used in film-making. The proposed method utilizes “Reliability” to compensate for errors that may have occurred in non-studio environments and to produce the most natural scene from the reconstructed model. By using a virtual camera control system, even non-experts can easily convert the 3D model to movies that look as if they were created by experienced filmmakers.

Algorithm-oriented generic libraries

We outline an approach to construction of software libraries in which generic algorithms (algorithmic abstractions) play a more central role than in conventional software library technology or in the object-oriented programming paradigm. Our approach is to consider algorithms first, decide what types and access operations they need for efficient execution, and regard the types and operations as formal parameters that can be instantiated in many different ways, as long as the actual parameters satisfy the assumptions on which the correctness and efficiency of the algorithms are based. The means by which instantiation is carried out is language dependent; in the C + + examples in this paper, we instantiate generic algorithms by constructing classes that define the needed types and access operations. By use of such compile-time techniques and careful attention to algorithmic issues, it is possible to construct software components of broad utility with no sacrifice of efficiency.     

Collaborative eScience libraries

In the context of collaborative eScience, digital libraries are one of many distributed, interoperable resources available to scientists that facilitate both human and machine collaboration: machine collaboration in the form of standards such as the Open Archives Initiative Protocol for Metadata Harvesting and human collaboration in the form of collaborative workspaces. This paper describes a set of collaborative workspaces created at the Los Alamos National Laboratory Research Library, initial patterns of use, and additional user requirements determined based on these initial patterns of use.     

OpenGL在屏幕保护程序中的应用

OpenGL是高性能图形和交互式视景处理的工业标准，文章通过VC 开发的屏幕保护程序来介绍OpenGL的一个应用。     

CDC 6000-series register save/restore

A CDC 6000-series central processor program to save and restore all programmable registers is presented. Comments on its utility and efficiency are included.     

Literate lives across the digital divide

In this literacy narrative, I describe the contexts and consequences of print and digital literacies in a globalizing world. Through a combination of personal and contextual details, I show how cultural, linguistic, and political milieus shape and are shaped by the literate practices in the digital environment. I also complicate issues of access and the digital divide and conclude by making a case for understanding cultural background vis-à-vis political history in order to understand individual literacy practices of students/writers.     

Synthesis from component libraries

Synthesis is the automated construction of a system from its specification. In the classical temporal synthesis algorithms, it is always assumed the system is “constructed from scratch” rather than “composed” from reusable components. This, of course, rarely happens in real life. In real life, almost every non-trivial commercial system, either in hardware or in software system, relies heavily on using libraries of reusable components. Furthermore, other contexts, such as web-service orchestration, can be modeled as synthesis of a system from a library of components. In this work, we define and study the problem of LTL synthesis from libraries of reusable components. We define two notions of composition: data-flow composition, for which we prove the problem is undecidable, and control-flow composition, for which we prove the problem is 2EXPTIME-complete. As a side benefit, we derive an explicit characterization of the information needed by the synthesizer on the underlying components. This characterization can be used as a specification formalism between component providers and integrators.     

Automation in American libraries

Despite its concentration on technical developments in library science, this survey is offered here because it is relevant to humanists for two reasons: first, that humanists all use libraries and therefore need to encourage their evolution to higher levels of efficiency, and, second, that the procedures outlined here may be of help to humanists in establishing procedures for their own research.     

Building large-scale digital libraries

In this era of the Internet and the World Wide Web, the long-time topic of digital libraries has suddenly become white hot. As the Internet expands, particularly the WWW, more people are recognizing the need to search indexed collections. The paper discusses some of the Digital Library Initiative (DLI) projects which are a good measure of the research into large scale digital libraries. They span a wide range of the major topics necessary to develop the National Information Infrastructure     

Software testing based on SDL specifications with save

The signal save construct is one of the features distinguishing SDL from traditional high-level specification and programming languages. However, this feature increases the difficulties of testing SDL-specified software. We present a testing approach consisting of the following three phases: SDL specifications are first abstracted into finite state machines with save constructs, called SDL-machines; the resulting SDL-machines are then transformed into equivalent finite state machines without save constructs if this is possible; and, finally, test cases are selected from the resulting finite state machines. Since there are many existing methods for the first and third phases, we mainly concentrate upon the second phase and come up with a method of transforming SDL-machines into equivalent finite state machines, which preserve the same input/output relationship as in the original SDL-machines. The transformation method is useful not only for testing but also for verifying SDL-specified software